package Filter;

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;

/**
 *编码转换器
 * @author Satifanie
 *
 */
public class SetCharacterEncodingFilter implements Filter{
	protected String encoding=null;
	protected FilterConfig filterConfig=null;
	protected boolean ignore=true;
	//destroy()
	public void destroy() {
		this.encoding=null;
		this.filterConfig=null;
	}
	//选择默认的使用的字符编码
	public void doFilter(ServletRequest request,ServletResponse response,
			FilterChain chain) throws IOException,ServletException
	{
		//选择使用的字符编码
		if(ignore||(request.getCharacterEncoding()==null)){
			encoding=selectEncoding(request);
//			System.out.println("encodeing");
			if (encoding!=null)
				request.setCharacterEncoding(encoding);
		}
		//将控制权交给下一个Filter
		chain.doFilter(request, response);
	}
	//这个将filter放置在服务中
	public void init(FilterConfig filterConfig) throws ServletException{
		this.filterConfig=filterConfig;
		this.encoding=filterConfig.getInitParameter("encoding");
		String value=filterConfig.getInitParameter("ignore");
		if(value==null){
			this.ignore=true;
		}else if(value.equalsIgnoreCase("true")) {
			this.ignore=true;
		}else {
			this.ignore=false;
		}
	}
	//选择适当的字符编码
	protected String selectEncoding(ServletRequest request) {
		return (this.encoding);
	}
}